# A000913 (b-file synthesized from sequence entry) 1 0 2 1 3 2 4 12 5 38 6 143 7 490 8 1768 9 6268 10 22610 11 81620 12 297160 13 1086172 14 3991995 15 14731290 16 54587280 17 202992808 18 757398510 19 2834493948 20 10637507400 21 40023577524 22 150946230006 23 570534370692 24 2160865067312 25 8199710635816